FIG. 16 is a drawing to show configuration and a programming operation of a programming tool with an FBD according to a related art. The operation of preparing an FBD of a programmable controller 109 connected through an information transmission section 106 by a programming tool 110 will be discussed.
Generally, the programming tool 110 with an FBD is made up of an FB library section 102 storing function blocks (FBs) 120, which the user will select, and an FBD editor section 101 for dragging and dropping the selected FBs 120 and connecting them, as shown in FIG. 16.
The FB 120 is a function block having an algorithm and data for implementing a certain function and having a hidden internal structure, and has input pins 121 as an input interface and output pins 122 as an output interface.
In the programming tool with the FBD in the related art, one FB is selected out of the FB library section 102 and the selected FB is placed at any desired position of the FBD editor section 1 by dragging and dropping with a mouse 107b. 
After placement, to connect between the input pin 121 of the FB 120 and the output pin 122 of another FB 120 placed preceding that FB 120 or the output pin 122 of the FB 120 and the input pin 121 of another FB 120 placed preceding that FB 120, one pin is selected by click operation of the mouse 107b and further the other pin to be connected is selected by click operation of the mouse 107b, etc.
This operation is repeated, thereby representing a processing flow and preparing a program.
In the programming tool in the related art, the operation of selecting an FB 120, placing the selected FB in the FBD editor section 101 by drag-and-drop operation, and connecting the FB 120 to another FB 120 placed preceding that FB 120 is repeated for preparing a program, as described above. Thus, as many drag-and-drop operations as the number of FBs in the program and the connection operation to each FB are required and there is a problem of very burdensome operation.